1. Field of the Invention
The present invention relates to a condenser for use as a cooler in automobiles, and more particularly to a condenser for such use, which is made of aluminum. Herein "aluminum" includes aluminum alloys.
2. Description of the Prior Art
In general heat exchangers as car coolers use a high pressure gaseous coolant, and they must have an anti-pressure construction.
To this end the known heat exchangers are provided with a core which includes flat tubes arranged in zigzag forms, each tube having pores, and fins interposed between one tube and the next. Hereinafter this type of heat exchangers will be referred to as a serpentine type heat exchanger.
The serpentine type heat exchangers are disadvantageous in that the coolant undergoes a relatively large resistance while flowing throughout the tubes. To reduce the resistance the common practice is to use wider tubes so as to increase the cross-sectional area thereof. However this leads to a large core, and on the other hand an accommodation space in the automobile is very much limited. As a result this practice is not always effective.
Another practice is to placing more fins by reducing the distances between the tubes. This requires that the height of each fin is reduced. However, when the fins are too small the bending work becomes difficult, and takes more time and labor.
In general the condenser has a coolant path which consists of two sections, that is, an inlet section, hereinafter referred to as "condensing section" in which the coolant is still gaseous, and an outlet section, hereinafter referred to as "supercooling section" in which it becomes liquid. In order to increase the heat exchange efficiency it is essential to increase the area for effecting heat transfer in the condensing section, whereas it is no problem for the supercooling section to have a reduced area for heat transfer.
The conventional serpentine type heat exchangers have a coolant passageway which consists of a single tube. It is impossible for a single tube to be large in some part, and small in others. If the tube is to have a wider crosssectional section the tube per se must be large throughout the entire length; in other words a large tube must be used. This of course leads to a larger condenser.
As is evident from the foregoing description it is difficult to improve the conventional serpentine type heat exchangers merely by changing the dimensional factors thereof.
Basically the serpentine type heat exchangers involve the complicate process which consists of bending tubes, and then assembling them into a core in combination with fins. This is why it is difficult to produce the heat exchangers on automatic mass production line. Non-automatic production is costly.